Traffic signal



Oct. 14, 1941.

P. G. HUGHES ET AL ,764

TRAFFIC SIG\NAL Filed Nov. 16, 1939 1.9" 10 r 0 I 16' I, Q

Ill UM/A/AT/A/G 1/6/9715 1NVENTOR5 BY Wx?) Mfim Warzfl/MATTORNEY:

Patented Oct. 14, v1941 TRAFFIC SIGNAL Patrick G. Hughes and Paul 0.Kock, Cincinnati, Ohio, assignors, to themselves and Carl R. Karst,Cincinnati, Ohio Application November 16, 1939. Serial No. 304,764

\ Claims.

This invention relates to traffic signals of the type embodying green,yellow or amber, and red lights for controlling the flow of trafllcthrough a street intersection. The invention is directed particularly toan improved signal for forecasting signal changes.

The traflic signals which are in use at the present time change abruptlyfrom green to red or amber, and vice versa. The operator of a vehicleapproaching such a signal light has no indication of the remaininginterval of time before the signal light will change. If the light bered as the vehicle approaches, there is relatively little hazardinvolved since a stop warning is given. However, if the signal be greenas the vehicle approaches, and then changes to red abruptly, there isdanger that the vehicle will collide with others proceeding inaccordance with the signal change. The use of amber lights, intermediateto the red and green signal l ghts, is helpful in protectingpedestrians, but such warning intervals have not been completelysatisfactory for controlling automobile traflic.

The primary object of the present invention since the last signalchange, or the interval of time remaining before the next signal change.

I Most trafiic signal apparatus in use at the present time is of arelatively standard type, embodying the signal lights themselves and anelectric controller for energizing them at predetermined periods. Thesignal lights are installed either at the street comers, or, in someinstances, a single four-way light unit is suspended at the center ofthe intersection. Four wires usually are strung from a signalcontroller, which may be located at a remote point, to the signal units;three of these wires usually are individual to the three respectivelights, red, amber, and green, and the fourth wire common to all. Thesystems usually are operated upon 110 volt potential. The object of thepresent invention has been to provide an indicator unit operable inconjunction with such a signal light system. deriving its current fromthe wires leading to the signals from the control box and deriving itsprimary control from the the light unit be controlled automatically fromthe primary control, or manually, as by a traffic ofilcer.

The preferred embodiment of the invention comprises a cabinet which isarranged for mountving adjacent or upon the signal light itself; if

there be four signal lights an indicator'is provided at each one, and ifthere be a single signal light at the center of the intersection, theindicator unit has four dials, each ,visible from a .given direction.Each indicator is comprised .of

an illuminated dial over which a movable pointer is exposed. An electricdrive is provided for moving the pointer about the face of the dial, andthe speed of the drive is synchronized with the primary signalcontroller timing, so that the pointer is driven through one cycle ofmovement during the interval in which-the green light is energized.

The electric drive means for moving the dial indicator is in circuitconnection with the :een signal light, and switch means r ponsive to themovement of the pointer is employed for breaking thecircuit to theelectric drive when the pointer has completed one cycle of indication.

The apparatus also includes interlocking switch means for maintainingthe synchronism of the indicator with the green light. This feature isconsidered to be of importance for two reasons:

It is well known that a signal device which is operated improperlyplaces a much greater hazard upon th trafllc than the employment of noneat all; and, on the other hand, it is frequently necessary for a tramcoflicer to operate the primary controller by hand, and such manualoperation may, and very likely will, upset the synchronism of theindicator with the signalling cycles when the system isreturned toautomatic operation if the synchronism be dependent entirely uponenergization of th green light circuit.

In the present apparatus, therefore, the interlocking switch means isarranged for energizing the electric drive unit from the red lightcircuit in those instances when or if the green light circuit isdeenergized before the pointer has completed a cycle of indication.

The drawing illustrates a preferred embodiment of the invention which issuited for installation directly upon the signal light of a comer typelight in common use at the present time.

Figure 1 is a face view of the assembly of the indicator and the signallights.

Figure 2 is a diagrammatic view of the circuit of the indicator, lookingtoward the back of the pointer dial. The heavier lines represent theleads being energized, while the lighter lines represent ;the leadswhich are idle. As shown, the circuit is being energized by the greenlight circuit of the primary trafllc controller Just at the start of itscycle. I

Figure 3 is a diagrammatic view of the circuit of the indicator as itappears at the beginning of a red light cycle, Just after an interruptedgreen light cycle, 1. e. one in which the green light circuit was brokenbefore the hand of the indicator could complete its cycle.

The indicator unit is comprised of a housing I, having a dial face 2 ofglass or suitable transparent or translucent material over which apointer 3 is disposed for rotation. The signal light itself upon whichthis unit is mounted is comprised of a framework 4, of pipe or conduit,for example; and the signal light unit housing the stop, caution, and gosignals, 5, 8, and 1 is carried within the framework. The iramework iscarried upon brackets 8 and 9; these usually are I2, one for each side,and these brackets are fastened upon the framework 4, for assembly ofthe indicator with the traffic signal unit. The upper conduit of theframework upon which the indicator is mounted is provided with an outletl3, for connection through a union 14 with an outlet 15 in the housing;and the leads to the indicator from the common and individual leads toth signal lights are taken through this con nection. The lead wires l6,l1, l8, and I9 from the primary trafllc controller enter the unit at theoutlet 20.

The mechanical details for the construction of the housing, and suchmodifications as may be necessary to adapt the unit for use inconjunction with traflic signal lights other than the type shown,readily will be understood by those skilled in the art and, for thatreason, are not here described in detafl.

As illustrated in Figur 2, leads i6, ll, l8, and [9 are taken from theprimary controller, which is indicated diagrammatically at 2|; the leadl6 being individual to the red light, the lead I! being individual tothe yellow or amber light, the lead l8 being individual to the greenlight, and the lead i9 being common to all three lights. The amber lighthas no connection into the indicator circuit, and therefore, the circuitis dead during the amber light interval.

The electrical circuit includes switches 22, 23, 24, and 25. Switch 22consists of a stationary contact 26 and a movable contact 21. Themovable contact is carried on one end of a pivoted switch arm 28. Theother end of the pivot arm.

is connected to an armature 23. The armature is actuated by either oneor the other of a pair of solenoids 30 and 3|. Solenoids 30, whenenergized, pulls the armature toward it and so serves to move thepivoted switch arm 28 and its contact 21 into a closed position withrespect to contact 26. Solenoid 3!, when energized, acts upon thearmature to open the switch 22.

As shown in the diagram, the switch arm 28 may be connected to thearmature-by a pin carlied on the armature acting in a slot in the arm,or they may be connected through a toggle arswitch arm 32 and lead 53.

of the motor is connected to the common lead rangement or other means,to keep the parts from binding as the pivot swings through its arc.

. Switch 23 is composed of a movable arm 32 carrying a contact 33 forengagement with either one oi two contacts a or b, both of which arestationary. Normally, a spring 34 holds the switch arm 32 and itscontact 33 in connection with contact a, but when a solenoid 35 isenergized, the spring tension is overcome by the solenoid. andthe'oontact 33 is brought into connection with the b contact.

Switch 24 consists of a movable contact 33 and a stationary contact 31.'The movable contact 33 is carried on the pivoted switch arm 33. Switch24 is opened'when a solenoid 33 is energized, its

armature 43 being connected to the pivoted switch arm .38. Switch 24 isclosed by a cam, indicated generally at 4|, acting upon the end 42 atits switch arm on the side or the pivot point opposit the contact. Thisclosing action is described at a later point in the specification.Switch 25 is comprised of a movable switch arm 43,-carrying a contact 44which swings in termediate two contacts 45 or 46, both stationary.Normally, the switch arm holds contact 44 in engagement with contact 43by action of spring 41; however, the end of theswitch arm is extendedfor actuation of it by cam means 4| for closure of contact 44 withcontact 43.

The cam is comprised cl. 0. disc or other suitable me'anskeyed to theshaft 43 which carries the pointer 3, so that the two, disc and pointer,revolve together. The cam disc carries a pin 49, which acts upon'the'end 42 of the switch arm 38 to swing it outwardly away from the center01 the disc, at which time, the other end of the pivoted arm bringsmovable contact 33 into engagement with stationary contact 31.

In continuing its course of travel, pin 43 acts on the end or switch arm43 opposite the contact to swing it outwardly from the center of thedisc in the same manner that it acted upon switch arm 33. The swingingoi the arm of the switch terval of time that the green light isenergized;

A lead 5| connects stationary contact 28 of switch 22 to the green lightlead it. Movable contact 21 of switch 22 is connected to a lead I2through its switch arm 28. Lead 52 intercomnects switch arm 23 andcontact a of switch 23. The movable contact 33 of switch 23 is connectedto one terminal of the motor 60, through its The otherterminal l3,through leads 54 and 55.

For the purpose of illuminating the dial lights so that the pointer willbe visible ,at night, a pin.

is taken from movable contact 44' to common lead I9.

Solenoids 33, 35, and 39 are served by lead M from the red light leadIt, as follows: Solenoid CYCLE or OPERATION (a) Normal synchronousoperation At the time the green light comes on, the various switches ofthe apparatus are as shown in Figure 2 of the drawing, and the circuitwhich is energized from the green light circuit is shown in heavy lines.At this time, in other words, the switch 22 is closed, switch 24 isopen, the movable contact 33 of the switch 231s in engagement with the acontact of that switch, and the movable contact 44 of switch 25 is inengagement with the stationary contact 45. The pointer is in thestarting position, as shown in Figure 2. As the green light comes on,leads i3 and I3 are energized and current flows through the lead l3, thelead switch 25, arm 21, the lead 52,through the contacts a and 33 .ofswitch 23 and to the motor 53 through the lead 53; the return circuitfrom the motor is through leads 54 and 55 back to the common lead l3.

At this time, solenoid 3! is dead due to the fact that the circuit tothis solenoid 'is open' at the switch 24. As the green light comes on,the lights 55 are energized since these lights are connected across theleads 52 and 55. The solenoid 33 and the solenoids 35 and 39 are deadsince these 8018-. noids are in circuit connection with the red light,which at this time is deenergized. v

When the green light is energized, therefore, the motor 50 rotates shaft43, and the pointer 3 and disc 4! are rotated so that the pin 43,carried on the disc, is moved past the arm 43, permitting the spring 47to retract the arm 43 and 'is in circuit connection with switch 24 andsubject-to actuation from the green light circuit, the circuit to thissolenoid was opened when con-'- tact 44 of switch 25 left contact 46.

The pin' 49 continues to rotate and eventually comes into contact withthe arm 43 of switch 25. The pin moves this arm so that contact 44 isreturned to'engagement with contact 45, completing the circuit throughthe solenoid 3|, which now is energized so as to open switch 22 andbreak the circuit to the motor 50; Thus, the circuit to the solenoid-3iis from the green light lead l8, through lead 51, solenoid 3!, lead 53,switch 24, lead 59, contacts 44 and 45 and lead 50 which is incircuitconnection with the common lead 13.

In summary, therefore; the circuit to solenoid 3lhappen at switch 24 andclosed at switch 25 at the start of the green light interval. Then, asthe pin 43 moves past arm 43, the circuit is opened at both switches 24and 25. Next, as the pin strikes arm 42, the circuit is closed at switch24 and opened at switch 25, and, finally, as the pin returns toengagement with arm 43,

the circuit is closed at switches 24 and 25 andtherefore the solenoid isenergized; but as soon as it is energized, it opens switch 22 to stopthe motor.

Under normal operating conditions, the pointer is at the normal startingposition when the red light is energized, switch 24 is closed and switch22 is open; contact 33 of switch 23 is still in engagement with the acontact of that switch, and contact 44 is in engagement with contact ofswitch 25.

When the red light comes on, current flows from the red light lead 45through the lead 6|, the solenoid 30 and the lead 63 back to the commonlead l3, whereupon the solenoid 33 is energized to effect the closure ofswitch 22. Since this switch is in the green light circuit, there is pin49 having struck the arm 42 during the preceding green light interval.

When the red light is energized during automatic operation of the deviceand under the conditions which have just been described, the

1 motor 50 does not operate since the green light is dead, and, themotor cannot derive current from'the red light circuit through the 17contact of switch 23 because contact 33 of this switch is in engagementwith contact a. Thus, during normal automatic operation of the circuit,when synchronism prevails, current from the red light circuit isutilized only for the purpos of closing switch 22 by energizing solenoid30 and opening switch 24 by energizing solenoid 33.

Therefore, by the time the red light cycle is completed, all of theswitches have been restored to their original positions and the circuitis ready to operat when the green light is next energized.

(b) Restoration and maintenance of synchronism As previously described,it frequently occurs that a trailic offlcer will operate the primarycontrollermanually. For instance, the tramc oflicer may. deenergize thegreen light before the pointer has completed its cycle of indication incases where traflic is very heavy in one direction and sparse intheother. Moreover, signal lights in the muncipalities usually are turnedoff entirely late at night and at such times the pointer may be stoppedin a position other than its normal starting position. The presentapparatus is arranged to accommodate such instances by effectingoperation of the motor and restoration of the switches to startingpositions, through energy derived from the red light circuit. When soenergized, the motor drives the pointer until the pointer has reachedstarting position, and then the apparatus proceeds to operatesynchronously '1 until the synchronism is again disturbed.

reached a position as shown, for instance, in Figure 3, when the greenlight is deenergized. As soon as the green light is deenerglzed, themotor 50 stops, switch 22 remains closed, contact 33 is in engagementwith a contact of switch 28, switch 24 is opened and, at switch 24,contact 44 is in engagement with contact 44 (since the pin 49 has movedout of engagement with arm 43 and the spring 41 has retracted the arm)As soon as the red light is energized, current flows through the leadIS, the lead ll, lead 44, solenoid 35, lead 65, through the contacts 44and 44 ct switch 25, and returns through lead 40 to the common lead i9.Energized solenoid -85 now retracts the arm 32 of switch 23 and bringscontact I! of this switch into engag'ementwith the b contact thereof,and, consequently, current is permitted to flow to the motor II throughthe leads l8, SI, 64, contacts 12 and 43 of switch 23, the arm 82 andlead I53, with the return circuit from the motor being through leads 54,I and it.

The solenoid 39 also is energized as soon as the red light comes on,with the circuit being through the leads l6, 6|, solenoid 39 and theleads 48, 55 and 19. The latter solenoid therefore opens switch 24.(This switch previously was-closed sincethe pin 48 had moved past arm 42but had not yet reached arm 43.)

The energized motor 50 drives disc 4| until pin 49 engages arm 43 tomove contact 44 into engagement with contact 46 and out of engagementwith contact 45. As soon as the contact 44 leaves contact 45,the-"circuit to solenoid 35 is broken. The solenoid becomes deenergized,and spring 34 retracts the arm 32 and brings switch 33 into en agementwith the a contact thereof.

s eaves soon as the red light circuit comes on, as Previously described.

On the other hand, if the pointer completes its cycle of revolutionbefore the green light is deenergized, then the pin 44 strikes the arm48 at the completion of the cycle of the pointer, contact 44 is movedinto engagement with contact 44 of switch 2!, the circuit to solenoid IIis completed, and this solenoid opens switch 22 which is in the motorcircuit, to disrupt the current supplied to the motor in this manner.

, primary controller for energizing the lights one As soon as contact33-leaves contact I) of switch 23, the circuit to the motor 50 is brokenand this motor therefore stops, leaving pin 49 in starting positionrelative to arm t3. Thus, when the motor has restored the pointer tostarting condition, its operation is discontinued whether or not the.primary red light circuit continues to be energized. At this, time,therefore, all switches are in initial starting position, and thecircuit is ready for operation by current from the green light circuitwhen it next becomes active.

During the red light interval, it will be noted, switch 22 is closed,since the solenoid 30 is energized as soon as the red light comes on,the circuit being through leads i6 and GI, solenoid 30, lead 83 andcommon lead l9. 4 In the preferred structure, arm 42 is in such aposition, relative to arm 43, that pin 49 will actuate arm 42 theinstant it leaves arm 43. Therefore, no condition can exist in which thegreen light, if deenergized, will place the device in an inoperablecondition. a

It will be seen that the motor Il may be stopped at the end of the greenlight interval in one of two ways, depending entirely upon the relativesynchronism oi the speed of the motor with the green light time cycle.Insofar as the operation of the device is concerned, it makes nodifference whether the green light circuit from the primary controllerbecomes deenergized before the pointer reaches starting position orafter the pointer has reached starting position. In the former instance,that is, if the green light goes out before pin 49 has engaged arm 43,then the motor stops running because its supply circuit has become dead,and the incompleted portion of the cycle of the pointer is completed asAs previously described, it is preferable to ad- Just the motor speed togreen light time interval, so that the green light goes out just as soonas the pointer completes its cycle, since there is less wear and usageof the parts.

Having described our invention, we claim:

1. A signalling device comprised of a circuit including a red light anda circuit including a green light, said circuits including, in common, a

after another consecutively for signalling cycles, the said controllerusually operating to control the green light for a predeterminedinterval of time, but capable of being controlled manually forcontrolling the green light for any desired period of time, a motor,electric circuit means for energlzing the motor from the circuitincluding the green light, an indicator driven by the .motor through acycle of indication during the interval of time the green light normallyis energized, said electric circuit for energizing said motor includingswitch means for deenergizing the motor when the indicator completes onecycle of indication, and circuit switching means for energizing themotor from the red light circuit when the indicator has not completed acycle of indigaztgn before the greenlight signal is deener- 2. A trafllcsignalling device, comprising, a combination of an electric circuitincluding a primary circuit controller for energizing a plurality ofsignals one after another consecutively for signalling cycles, the saidprimary circuit controller usually operating to control a given one ofthe signals for a predetermined period of time, but capable of beingcontrolled manually for controlling the given one of the signals for anydesired period of time, a motor, electric circuit means for operatingthe motor through the circuit of the given one of the signals when thecircuit is energized from the primary controller, an indicator driven bythe motor at a predetermined speed for completion of a cycle ofindication during the interval in which the said given.

one of said signals normally is energized, said electric circuit meansfor operating said motor including electric switch means fordeenergizing J the motor when the indicator completes one cycle ofindication, and means for driving the motor from the next successivesignal circuit when the preceding signal circuit is deenergized beforethe indicator has completed a cycle of indication, for completion of thecycle of indication.

3. A signalling device comprised of a circuit including a cautionsignal, a danger signal and a safety signal, said circuit including aprimary controller for energizing the signals one after another forsignalling cycles, the said controller usually operating to controlthesafety signal for a predetermined period of time, but capable ofbeing controlled manually for controlling the safety signal for anydesired period of time, an indicator, and electric circuit includingmeans for driving the indicator through a cycle of indication during thenormal intervaiin which the safety signal is energized. circuit meansincluding the safety signal circuit for energizing the electric drivingmeans when the safety signal is normally energized, switch means inconnection with said electric circuit for drivin said indicator, saidswitch means operated by said indicator when the indicator completes acycle of indication ior deenergizing the electric drive, and circuitswitching means including a switch responsive to the position oi. theindicator for energizing the electric drive means through the dangersignal circuit it the. safety signal is deenergized before the indicatorhas completed a cycle of indication.

4. A trafiic signalling device of the class described, comprising, afirst signal circuit and a second signal circuit, said circuits normallybeing energized consecutively each for a predetermined period oftime,but with the said first signal circuit occasionally being energizedfor a timed interval different from the predetermined period, a motornormally in circuit connection with the first signal circuit foroperation when the first signal circuit is energized, an indicator indriving connection with the motor for operation through a cycle ofindication during the period of time in which the first signal circuitnormally is energized, circuit switching means actuable responsivelytothe position of the indicator and providing circuit connection of themotor to the a cycle of indication, and switch means actuable inresponse to the completion or the cycle of indication for uncircuitingthe motor from the second signal .circuit and reestablishing circuitconnection to the motor from the first signal circuit for operation ofthe motor when the first signal circuit is next energized.

. 5. A traflic signalling device oi the class described, comprising, a,first signal circuit and a second signal circuit, said circuits normallyenergized consecutively each for a predetermined period or time but withthe first signal circuit occasionally being energized for a timedinterval diflerent from the predetermined period, a motor normallyincircuit connection with the first signal circuit for actuation in.unison therewith, an indicator in driving connection with the motor, thesaid motor normally driving the indicator through a complete cycle ofindication during the period of energization of the first signalcircuit, a

circuit controlling switch having actuating means second signal circuit,whereby the motor is driven therefrom tor completing the cycle ofindication of the indicator it the first signal circuit is deenergizedbefore the indicator has completed of indication.

connected with the second-signal circuit, the said actuating means beingadapted to operate said circuit controlling switch for deenergizing themotor when the indicator has completed a cycle 0'! indication, and meansfor maintaining synchronism between the position of the, indicator andthe intervals of energization of the first signal, comprising, circuitswitching means eilective ior energizing the motor through the secondsignal circuit when first signal circuit is deenergized before theindicator has completed a cycle m'mrcx a. HUGHES. PAUL 0. zoom

